working long hours, woking for long hours

working long hours, woking for long hours working in long hours用法对吗 He is used to the long working hours甚么意思? Working long hours may kill you?（同义句） work long time 就是 work long hours long times 与 long hours 的区别. He w____ very long hours they often study( ) long hours -How long did you skate?-I skated for two hours. works very long hours 为什么不用介词for Some Chinese students often___very hard for long hours A pla 对two hours提问 和对 for two hours提问 都是用how long吗 为什么